linux makefile 框架分析2

[194] ifeq need-sub-make = 0

该篇主要分析这部分主makefile内容

[1906] end need-sub-make

[211] C: 源代码check, KBUILD_CHECKSRC

[220] M: 指定外部模块目录，KBUILD_EXTMOD

extmod-prefix: 外部模块路径

ifeq ($(abs_srctree),$(abs_objtree))srctree := .building_out_of_srctree :=
elseifeq($(abs_srctree)/, $(dir $(abs_objtree)))srctree :=elsesrctree := $(abs_srctree)endifbuilding_out_of_srctree := 1
endif

objtree := .

VPATH := $(srctree) 为什么不直接用绝对路径

version_h

clearn-target :=

no-dot-config-targets

no-sync-config-targets

single-targets:

config-build：

默认空，如果KBUILD_EXTMOD为空，且MAKECMDGOALS包含%config，置1；

mixed-build：

默认空，

如果KBUILD_EXTMOD为空，且MAKECMDGOALS包含%config，且多于1个 goals，置1；

如果MAKECMDGOALS 包含有single-targets，且还包含有其他，置1;

如果MAKECMDGOALS包含有clean-targets，且还包含有其他，置1；

如果MAKECMDGOALS包含有install，和modules-install，置1；

need-config:

默认是1，如果MAKECMDGOALS 只包含 no-dot-config-targets，清空；

may-sync-config:

默认是1，如果MAKECMDGOALS 只包含no-sync-config-targets，清空；

如果KBUILD_EXTMOD被定义，清空；

single-build:

默认空，如果MAKECMDGOALS包含single-targets，置1；

[327]ifdef mixed-build

递归构建每一个goals

__build_one_by_one: for $(MAKECMDGOALS):make -f $(srctree)/Makefile each

[343]else mixend-build

单个构建的处理放在下面分析

[1905]end mixend-build

单个构建的处理分析

include scripts/kbuild.include: 各种makefile函数的定义

KERNELRELEASE KERNELVERSION

include scripts/subarch.include: 获取宿主机架构SUBARCH

ARCH ?= $SUBARCH: 交叉编译的话，需要提前指定ARCH

UTS_MACHINE := $ARCH

SRCATCH := $ARCH

KCONIFG_CONFIG ?= .config

KBUILD_DEFCONFIG := defconfig

HOST配置：编译选项，shell等

[430]交叉编译器配置：

CC = $(CROSS_COMPILE)gcc

LD = $(CROSS_COMPILE)gcc

.......

[472]各种FLAG：

CHECKFLAGS：

NOSTDINC_FLAGS:

CFLAGS_MODULE:

.........

[483]USERINCLUDE

LINUXINCLUDE

KBUILD_XXXX

[539]config 目标和 build 目标共享的规则

scripts_basic: 基础的辅助构建， make $(build)=scripts/basic

outputmakefile: 如果obj和src不是同一个目录，在obj目录生成makefile，根据前面定义的宏building_out_of_srctree来判断是否需要

CC_VERSION_TEXT

[592] end config 目标和 build 目标共享的规则

[594] ifdef config-build

include arch/$(SRCARCH)/Makefile: 获取KBUILD_DEFCONFIG定义

%config or config: outputmakefile scriptps 构建kconfig

make $build=scripts/kconfig $@

[611]else config-build

build目标构建分析

[1904]end config-build

build目标构建分析

[612]config-build = 0

__all: 如果定义KBUILD_EXTMOD，则依赖modules，否则依赖all

KBUILD_MODULES:

默认空；

如果MAKECMDGOALS包含 all modules nsdeps，则置1；

如果MAKECMDGOALS为空，则置1；

KBUILD_BUILTIN:

默认1；

如果MAKECMDGOALS 是 modules，则清空；

include include/config/auto.conf: 如果定义 need-config，则包含。里面包含了kconfig生成的所有配置

[654]KBUILD_EXTMOD为空: 构建vmlinux

core-y := init/ usr/

drivers-y := drivers/ sound/

drivers-$(CONFIG_SAMPLES) += samples/

drivers-y += net/ virt/

libs-y := lib/

[661]end KBUILD_EXTMOD为空

all: vmlinux all 默认目标

[669] 一些编译选项的宏

include arch/$(SRCARCH)/Makefile: 可以在这个目录增加架构相关的配置

[690] ifdef need-config

[691]ifdef may-sync-config

include include/config/auto.conf.cmd: 定义了 kconfig文件的依赖关系，以及auto.conf，确保这些可以是最新的

%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h: $(KCONFIG_CONFIG)

make -f $(srctree)/Makefiel syncconfig

[715]else may-sync-config

include/config/auto.conf: ????

[730] end may-sync-config

[731] end ifdef need-config

kBUILD_xx：编译选项控制

[961] include-y: scripts/Makefile.xxxx

KBUILD_IMAGR ?= vmlinux

INSTALL_PATH ?= /boot

INSTALL_DTBS_PATH = $(INSTALL_PATH)/dtbs/$(KERNELRELEASE)

MODLIB = $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)

module strip compressed sign: 相关操作

[1096] MODORDER: $(extmod-prefix)modules.order

MODULES_NSDEPS: $(extmod-prefix)modules.nsdeps

[1099] if 没有定义KBUILD_EXTMOD

core-y += kernel/ certs/ mm/ fs/ ipc/ security/ crypto/ block/

vmlinux-dir = core-y core-m drivers-y drivers-m libs-y libs-m

vmlinux-alldir = vmlinux-dir Documentation core- drivers- libs-

subdir-modorder = core-y/modules.order core-m/modules.order libxxx driversxxx

build-dirs = vmlinux-dir

clean-dirs = vmlinux-alldirs

KBUILD_VMLINUX_OBJS = head-y core-y/built-in.a libs-y/built-in.a drivers-y/built-in.a

ifdef CONFIG_MODULES(来自kconfig), += libs-y/lib.a

KBUILD_VMLINUX_LIBS =

ifdef CONFIG_MODULES, +=libs-y(非/结尾)，否则libs-y/lib.a

KBUILD_LDS = arch/$(SRCARCH)/kernel/vmlinux.lds

KBUILD_ALLDIRS: 供 scripts/Makefile.package使用

vmlinux-deps = KBUILD_LDS KBUILD_VMLINUX_OBJS KBUILD_VMLINUX_LINBS

autoksyms_recursive:

ifdef CONFIG_TRIM_UNUSED_KSYMS

KBUILD_MODULES = 1

autoksyms_recursive: descend modules.order

shell $(srctree)/scripts/adjust_autoksyms.sh :

make -f $(srctree)/Makefile vmlinux

endif

autoksyms_h quiet_cmd_autoksyms_h cmd_autoksyms_h

autoksyms_h: xxxx

ARCH_POSTLINK: arm没有

cmd_link-vmlinux: ld

vmlinux: scripts/link-vmlinux.sh autoksyms_recursive $(vmlinux-deps)

targets := vmlinux

vmlinux-deps subdir-modorder : descend

archprepare: outputmakefile archheaders archscripts scripts include/cnfig/kernel.release ... include/generates/autoconf.h

prepare: prepare0 prepare-objtool preprare-resolve_btfids

asm-generic

[1270] kernel header：生成和安装

[1307] kernel selftest: 运行自检脚本

[1324] devicetree file:

[1370] modules ifdef CONFIG_MODULES

modules: vmlinux modules_check

make -f scriptes/Makefile.modpost

cmd_modules_order =

[1440] else CONFIG_MODULES

[1675] else KBUILD_EXTMOD

[1729] end KBUILD_EXTMOD